#include<iostream>
#include<vector>
using namespace std;

int main(){
    int a,b,c;
    cin>>a>>b>>c;
    int flag=1;
    if((a==0&&b==0)||(b==0&&c==0))cout<<"NO";
    if(a==0){
        if(b==1&&c==0)cout<<"YES";
        else if(b==-1&&c==0)cout<<"YES";
        else cout<<"NO";
    }
    else if(a==1){
        if(b!=0)cout<<"NO";
        else {
            //b=0
            if(c!=-1)cout<<"NO";
            else cout<<"YES";
        }
    }
    else{
        //a=-1
        if(b!=0)cout<<"NO";
        else{
            if(c!=1)cout<<"NO";
            else cout<<"YES";
        }
    }
}
